I hope to carry out two major experiments. First, I will examine the neural interactions between pairs of cat retinal ganglion cells using the same spike train analysis methods I have used on LGN neural pairs. These data will be collected on one transcleral electrode and a second independent optic tract electrode. We hope these data will: 1) allow us to better interpret already existing data that deals with a serial synapse in the LGN; 2) Give us insight into the kinds of inputs shared by ganglion cells as well as the connectivity rules for these inputs (e.g., do homogeneous and heterogeneous fields share inputs as strongly as only heterogeneous fields? The second experiment will examine the neural interactions between pairs of cat retinal ganglion cells and lateral geniculate cells. These data will be collected on one transcleral electrode and a second independent lateral geniculate electrode. We hope these data will: 1) confirm or disconfirm our model of inhibitory inputs to cat LGN; 2) confirm or disconfirm some pilot data which suggest that the function of a serial synapse in the LGN is to either filter or generate specific spike intervals.